OnStep replacement board for EQ 6 Pro

OnStep replacement board for EQ 6 Pro on base [Howard Dutton](https://onstep.groups.io/g/main/wiki/3860) project
Key properties:
* Easy replacement of the original Synscan board (four screws and reconnect three wires)
* Big USB B port
* Bluetooth
* Wi-Fi
* Internal real time clock and PPS with battery backup
* Port for polar scope illuminator
* Three-channel controller for dew heaters or fans
* DSLR timer
* Weather sensor - temperature, pressure and humidity

Wiring diagram and PCB are on [EasyEDA](https://oshwlab.com/hujer.roman/onstep-for-eq6).

Pinmaps is based on MaxESP3 but requires the following minor modifications:


#define Aux7 36 // 36 is internal DS3132 PPS or 39 external (GPS) PPS
#define OneWirePin 15 // OneWire
#define ReticlePin 19 // Polar scope iluminator
#define TonePin 2 // Tone

// PEC Optional - not use now
#define PecPin 39
#define AnalogPecPin A3 // PEC Sense, analog or di